1. Field of the Invention
The present invention relates to a reciprocating saw.
2. Description of the Prior Art
A conventional reciprocating saw includes a mechanism for converting the rotation of a motor into a reciprocal movement of a saw blade in a longitudinal direction of a body. In this mechanism, a gear is rotatably driven by the motor within a horizontal plane. A slider is horizontally slidably supported by the body. The gear is disposed below the slider and includes an eccentric pin. The slider includes, on its lower surface, a recess extending in a lateral direction for engagement with the eccentric pin. Further, in order to reciprocally pivot the saw blade in a vertical direction in addition to the reciprocal movement in the longitudinal direction, Japanese Laid-Open Utility Model Publication No. 60-75002 discloses a mechanism in which an annular recess is formed on the upper surface of the gear. The annular recess has a depth varying in a circumferential direction. A rolling member such as a ball and a roller is supported by the rear portion of the slider and are in engagement with the annular recess for rolling movement therewithin. As the gear is rotated, the engaging position of the rolling member varies, so that the slider is reciprocally pivoted in the vertical direction.
Since the reciprocal pivoting movement of the slider is obtained through rolling movement of the rolling member relative to the annular recess, the prior art reciprocating saw involves the following disadvantages:
A. The rolling member and the surface of the annular recess are rapidly abraded by mutual rolling contact. This is particularly remarkable when a large load is applied to the rolling member because of the load applied to the blade. PA1 B. The rotational speed of the rolling member is determined by "Rotational Speed of Gear X Radius of Annular Recess .div. Radius of Rolling Member". Since the gear is rotated at high speed in this kind of reciprocating saw, a problem may be caused in the strength and the abrasion of the rolling member. PA1 C. Since the rolling member receives the load from the slider through point contact, the rolling member may be easily damaged. PA1 D. Since a particular machining operation is required to form the annular recess on the gear having the varying depth, the machining operation is very troublesome. PA1 a body; PA1 a slider supported by the body such that the slider is slidably movable in a longitudinal direction of the body and is pivotally movable in a vertical direction; PA1 a rotary member disposed within the body and rotatably driven by drive means; and PA1 a first motion conversion mechanism and a second motion conversion mechanism disposed between the slider and the rotary member, the first motion conversion mechanism being operable to convert the rotational movement of the rotary member into a reciprocal movement of the slider in the longitudinal direction, and the second motion conversion mechanism being operable to convert the rotational movement of the rotary member into a reciprocal pivotal movement of the slider in the vertical direction; PA1 the second motion conversion mechanism including: PA1 the abutting position of the other end of the arm on the abutting surface is varied as the actuating member is rotated, so that the vertical position of one end of the arm is varied.